In semiconductor devices such as semiconductor diodes, insulated gate bipolar transistors (IGBTs) or insulated gate field effect transistors (IGFETs) a low doping concentration of a base material such as a wafer before front end of line (FEOL) processing serves for realizing a DC voltage blocking requirement of the semiconductor device. A low doping concentration of the base material has the effect that the space charge zone propagates very far, which has to be compensated for by means of an increase in chip thickness of the semiconductor device if the intention is to ensure that the space charge zone does not reach a rear-side contact region.
In order to keep down the chip thicknesses, it has been proposed to introduce a field stop zone, that is to say a zone of increased doping with respect to the doping of the base material, in the semiconductor volume of the semiconductor device, which zone may be configured in stepped fashion, for example. The field stop zone allows for absorption of voltage or decrease of the electric field strength over a lateral distance that is smaller compared to the base material.
When manufacturing a field stop zone, a trade-off between a variety of characteristics such as low device leakage currents, cost-effectiveness and process compatibility with respect to temperature budget requirements.
It is desirable to provide an improved method of manufacturing a semiconductor device comprising a field stop zone.